Cosmetologists are primarily defined as hairdressers who work in retail or home-based salons. They constitute a major occupational group of female workers who sustain chemical exposures during their reproductive lifespan. In fact, it is estimated that there are between 500,000 and 750,000 cosmetologists in the United States alone, and that 80-85% of these workers are women. In general, cosmetologists are exposed to a variety of chemicals on a daily basis, including bleaches, hair dyes, non-lye relaxers, alcohols, methacrylate, ethylene glycol, and pthalates. Although several of these chemicals are known to cause reproductive dysfunction in animal models, few studies have examined whether they are associated with reproductive dysfunction in humans. In addition, no studies have examined the underlying mechanisms by which chemical exposures in cosmetology businesses are associated with reproductive dysfunction in women. Thus, the proposed work will test the hypothesis that exposure to chemicals used in cosmetology businesses is associated with reproductive abnormalities in women through mechanisms involving destruction of ovarian follicles. To test this hypothesis, this work will: 1) determine whether cosmetologists have an increased risk of reproductive abnormalities compared to women who are not cosmetologists and 2) investigate whether cosmetologists have reduced ovarian volume and follicle numbers compared to women who are not cosmetologists. To complete the proposed work, a cross-sectional study will be conducted in 1500 female cosmetologists and 500 women not exposed to chemicals used in hair/nail salons (i.e., retail sales clerks). Each participant will complete a self-administered questionnaire that assesses demographics, reproductive functioning, medical and lifestyle history, and chemical exposures. A subset of women from the cross-sectional study (30 infertile cosmetologists, 30 fertile cosmetologists, and 30 retail sales clerks) will have a transvaginal ultrasound to measure ovarian volume and follicle numbers. Data from the questionnaires will be used to compare reproductive function in cosmetologists and retail sales clerks. Data from the transvaginal ultrasounds will be used to compare ovarian volume and follicle numbers in cosemetolgoists and sales clerks. The results of this study will help determine whether exposures in cosmetology businesses are associated with reproductive dysfunction in women.